Cats have lots of funny behaviors. Chief among them: many people report that their cats like to sit on their humans' clothes that have been left out in the open. What is it about our clothes that causes this cat behavior? Why does your cat sit, lie or sleep on your clothes?
Clothes are soft
Let's start with the obvious: clothes are soft and comfortable to lay on (or at least, certain types of clothes are). A pile of clothes left out in the living room or bedroom provides a cozy, soft surface for your cat to snuggle up on. Some cats like to mix it up between laying on their cat beds and laying on various other surfaces throughout the day, and that pile of clean clothes or dirty laundry may be just another comfy sleeping spot that makes it into your cat's daily rotation.
Your familiar scent is comforting
Your clothes smell like you! Veterinarian Dr. Karen Primm believes the behavior of sitting, lying or sleeping on clothes goes back to a cat's instinct to survive. She points out that when wild felines live in a "family group," they share resources and communicate the value of these resources to other members by scent marking.
Because you have (unintentionally) scent marked your clothes with your pheromones, your cat may perceive these clothes as safe or comforting. As Dr. Primm puts it, "your clothes bear your scent and it is like a sign posted for your cat that says, 'I have checked these items out and they are alright.'" It's a familiar scent that is comforting to your cat. You may see your cat displaying "cozy" behaviors, like kneading or purring, when they are on your clothes for this reason.
Cats also like to leave their own scent on things they want to mark as "theirs," and lying on your t-shirt or sweater accomplishes this task too.
The behavior has been reinforced
It's possible that your cat has gotten attention (either positive or negative) in the past for sitting on clothes. For example, maybe once they sat on a clothing item and you said "aw!" and came over and petted them for being cute. Even if this sequence of events was incidental, your cat may have learned that lying on clothes leads to petting and attention.
The same thing can happen even if you didn't want the cat on the clothes — for example, if your cat sat on the black t-shirt you were about to put on, and you said "Fluffy, get off my shirt!" If your cat finds attention rewarding, it's possible that just speaking to them in this instance reinforced the behavior of sitting or lying on the clothes. ("When I laid on their t-shirt, my parent talked to me right away!")
Clothes are (kind of) like a small box
Most cats love anything that resembles a small space or confined area, likely because it provides a feeling of safety and security. Clothes, especially t-shirts or other tops that are relatively square-ish in shape, might fit that description closely enough. Famously, many cats will get inside any square-shaped object, even if it's just a square of tape on the floor.
Your clothes may provide a similar (enough) feeling, or at least be the closest thing your cat can access to this feeling at the time.
Should I worry about my cat sitting or lying on my clothes?
If your cat sleeps, sits or lies on your clothes, you most likely don't need to worry: this is a common behavior and does not necessarily imply separation anxiety or other concerns.
If this is a new behavior, or is accompanied by other changes like excessive meowing, changes in sleep or eating habits, or anything else that feels sudden or "off" to you, it's always a good idea to pay a visit to your veterinarian.
The bottom line
Cats may sit or lay on your clothes because they're soft, because they smell like you, because the behavior has been reinforced, or because a pile of clothes resembles a cozy confined space to them. So next time you catch your cat getting their white hair all over your black dress, don't get too mad: they're only doing it because they love you (more or less).